Metallurgical process



' EN. E. GRENNAL'B" METLLURGCAL FROGESS Filed April 6 19523 A MineTallmg C t Oxldlezedore oncen amor i f @mantra e.

' l. Crushed. Maite n i Prenoms Matt@ News 120mm@ f t t Pesldue 'f lnROELS m9 Premousieai '-6. 4.... k .4 Oxgzed Furnace.) Sepmr Leachmg n vA Tank S02 Roasted, Copper C@ Crusher Connbdce SoluUO-n Cop r PiaggeSmelilng C Furnace 5mg.

opper cw Soluuon `6- 502 gering U'flae Y SO2 Reducer Separator Separator-e N-Ol No2 Mlxer Ore or ,w Concentl'ate,

H CO

Ppe? E a Soluhon v Ileue.

- Soz o y I 50 Cer I Eectrogzed Solirwn 2 Eleci'mlgzlc,

Coitwfa Elecogzed. l t 0.-, Solulon L f yReduced Copperollfhon.

Electrolyzed. Soluclon j COPPS' INYENTOR lll Patented .lune 23, 1925.

Unirse STATES PATENT nFFicE.

WILLIAM E. GREENAWALT, OF DENVER, COLORADO.

METALLURGICAL PROCESS.

Application filed April- 6, 1923. Serial N'o. 630,309.

To all 'whom '15- mag/ concern.'

Be it known that I, WILLIAM E. GRnnNA WALT, a citizen of the UnitedStates, residing in the city and county of Denver' and State ofColorado, have invented certain new and useful Improvements in Metallui'gical Processes, of which the following is a specification.

The invention is more specifically directed to the extraction of copperfrom its ores, especially from its ores containing precious metals, by acombination of hydro and pyro metallurgy.

due would assay 'approximately 2.0%, or

40 lbs., copper, per ton, $1.25 in gold, and in silver; or a total metalcontent of gold, silver and copper of approximately $8.50 per tonestimating copper at l5 per pound. The recovery of these widelydifferent values by a solvent process, in so lean a material, wouldpresent quite a problem.

On the other hand, by the proposed process of leaching and smelting thediiculty is greatly reduced, and certain incidental advantagesareobtained which greatly facili lates the treatment of this class ofore.

vln smclting copper ore by the ordinary method, the` metallic copper isnot the end product, as is Well known. The ore is first smelted intomatte; this matte is then blown into blister copper, and the blistercopper is then refined electrolytically to obtain the copper of commerceand to separate and recover the precious metals, originally contained inthe ore. Conversion of the matte, and electrolytic relining areexpensive to operate, and certainly very expensive to install. Therefining installation is in fact so expensive that very few miningcompanies do their own refining.

LInthe present process electrolytic copper and the precious metals areobtainable in their elemental form without either a con?y `a sulphideconcentrate.

verting plant or an electrolytic refinery. It also simplifies leaching,Asince no strenuous eilort need be made toA get a high recovery in theleaching operation, and the leachingr step of the process, both ininstallation and operation can be greatly simplified. The installationof a smelting furnace, of itself, is not very expensive; the greatestexpense is in# curred. in the accessories. In the present process mostof the accessories of smelting are eliminated.

The process may be described by referring to the accompanying drawing,which represents a tlow sheet in diagrammatic plan.' Ordinarily, the lowgrade ore, as it comes from the mine, is concentrated, either bygravity, by flotation, or both combined, into The gangue is wasted.' Ifthe ore is partly in the form'of .oxide the tailing may be leachedseparately.

In the operation of the process the suL- phide concentrate is roasted,preferably by the method set forth in n1 pending application, Serial No.485,885, led July 19, 1921, by means of which from 50% to V75% of thecopper can be made soluble in water. The roasted concentrate is thenleached with an acid solution to extract the copper. The leaching ispreferably done by agitation. The resulting solution is then treatedwith sulphur dioxide, obtained from roasting the sulphide concentrate,to reduce the ferrie salts in the solution to the ferrous condition. Thesolution is then electrolyzed to deposit the copper as the electrolyticmetal with the simultaneous regeneration of the solvent.

The cycle of reduction and electrolysis is continued until the solutionis suicientl depleted in copper and regenerated in acidi Thisregenerated acid solution is then returned to the ore to dissolve thecopper'no't soluble in water. This step of the present process isdescribed in detail in my apparatus Patent No. 1,353,995, Sept. 28,1920; and in my pending process application, Serial No. 520,241, filedDecember 6, 1921.

The leach residue, which doesnot require a high extraction andconsequentlyV not 'a thorough washing, or possibly no washing at all, isthen mixed with a combustible, and preferably with enough rawconcentrate to',

provide suiiicient sulphur tofor-m a suitable l lll 4 gratie tlicx-rted,an

'amount of. moisture forA siie'teriug. 'which lis ordinarily about 10%.`ltwl-not be neces-A sary, tl'iereoreV to liltertlfie leech residue orlto dry it before mixing it withy hthe material., The mixture oloreandleacb residue is then eintered.; azul tl'iesinter smelterlmtomatte, 'This mette contains,' ila a. comparatively small bulk, all tllel'esiflual'yaluesf'- lwith eliig'b. percentage el recovery and a sultiug*very lean-slag, with e high ratio: oit concentration.

vll'iere lle matte of eo...paratively lowl liigbrecoyery, andconseiuiently a high rate o sineltim.

A 'Vlllhior exertiple, the] originel ruw` concentrate essaya lf; copper,end tliesleg 0.2%; a. recovery of approximately Qtlffyboit thecopperin-- d'coneequeutly Valec "ol: the pre1- eioue metals. li? the matteismaintainell i' 'at 30.0% copper7 jwljiicb ie noi/...a ve'l'y-liigllgrade; aA concentration ol" 4 can Vbe marie of the leach residu-e. Thiswould give 'aMinatte containingelso about' .$35.00 iu gold 21ml silver..Su'cli e. matte Wou-ld be ,of entirely too low e grade to War'- Vrantspecial treatmentilortlie recouery of -tlre lfareciousniet'ale Themattefis crushed- ,copper and precious metals7 Witl'ioutany :lo recoverthe pr to' about the same lin'eness vas tljiei Mince.- trate, and istlien mixed witlrthe raw coneeutriate, 'and the mixture" forms a- 'newcl'iarge. The 'mixture will l-a\'fe approximately copper furl aooutflLOOin golcl and silver. l`lieuiirtureie tl'ieo roast'- erl and lcaclieti'and 'the residue ei'nelteol as described. .The reeultiug matte willassay lthis -way tlic presione. metalyalues in ,the

matte are built up to 'any extent desired? .special treatment? 'sind thegang-neet (lie mnceutrate is; eliniinateu as u ,low 'glade slug.:.xeeeyingla-bout 0.2% copper'. When the ruelle ifs snl'liciently builtup on the prei zriouenfeale. itisWithdrawn 'trom tlle oir cuit, am!uitl'ner shipped, or en a Special treatlneutg by crualiing the -inertieroasting' Atin a sin-ill superate. liuruzu'e, :u1-2l leaching end tlieiitreating' llxe.leaclwfl multe rceiilu'el azione unitair'. m'nletallicYorin by any ci the well lroouu inelliorls,

li' as aumlifamation, elrloriiialionggorcyf` a `ooiul iuili m ult thesereSu'lt-i al. le matte lation,

` 'lbe to. rees;

tremely lcon slag le possible, ae Weil4 the v meppel solution like 'cop-Leeaeae per is aclrlerl4 to 'regular copper solutiou :mtly `will notrequire any yfurther cere. The

Amatte residue isalso arlled to a new'eliarge of concentrate and henceno attempt need be. made` to get/va. low grade @ailing of the matte,and. lieuce'no great reliucm'eut is .ree

quired in Vthe treatment ot' thematte. l

llt wi'lllbe observed that in tl 'sinetliocl el treatment all the`metals are'recovered il,

metallic for-irl a'nol'in a vm'ercbantab'le condi?" tion, mtl with? anAexceptioanel high pereeutege. of 'reco-very, Without the use-'ot Aconverting or refining plarrt, and also w1thout any s peial 'reliueineutiiir the leaching ot' the couceutrate or expenser in tlie leaching zinstallation.

' The smellingle alsogreatly'clieapeueol;lf,

l exemple, the concentrate were Sm'elted direct, in a r eye-rbereto'ryVfurnace,v the concentrate 'wou'lcl'have tol lie-roasted, as in leaching,although notas carefully; ll. av L#3% copper matte is madetlieratiootcou: centrationV would be'ouly S'into "l, both for the copperand the precious metals, and, with a matte so vhigh .in coppe@ tl'feslag'would'be correspondinglyhigh, and considerable care would berequired to avoid excessive lossin per-ami about $6.00 in gold andsilver,

would' Abe nothing more than. a concentrated product, and would stillhave .to be'sllippecl,

converted ainlfreued tov get the metals in.v

n'ierclmutebleform; 1 f

By tbe present/processelle matte can be bunt up ru precious' metals 'to'any extent angl silver, peifton, for' a 30% copper matte, anal- 1t themette is. concentrated to Alo/1' about 95025.00. paretively 'very'lfliisyro'uld mean a coing small vinstallation or the olesired, 'or Sayup to about 95500.010'i-n gold eoppe,`tl1e gold and silver value wouldbe l recovery Aolthe precious metal values' in' metallic lt is evidentthat by thepresent process, the.

s'te'p olf leaching is greatly sim-plilied. A

ligli extraotiom'by leaching, Vis notneces.

sary,- sincc 'the residual copper recovered. nl the smeltrno'. lnordinary processes of leaching, wusbmgof the ore or residue to rinnovopractically all the soluble copper,

quite a tedious and expensive'operation, and in Sonie ceses, u'lleletllecopperiS eleutrolytically precipitated, :fully 25% of tlxe ooppcrj'lil-oni Waste i'o'ul 4Solutiones unil from waalx waters, isprecipitated "chei'rlically with Scrap iron, to .make ythe electrolytic(lepoeiti'oupractical; By the' present process all tine would beayoulecl, or practically eo, since there would be-no object in removingevencaw larve' portion of tige soluble cop.-4

leaoli residue'.v

llfitleutly, tlierefore, bo

'and the emelting are greatly clieapen'erl end sin'iplitled.

tb .tlleri'leachingf lie coal or coke, but ispreferably a suliicient nlin aiiiount of sulphide ore or concentrate to gi ve enough heat tosinter the mixture and to provide enough sulphur to give a desiralilematte. Sulpliide ore may also be added to the sinelting furnace. Underthese conditions of sintering it Will not he necessary to dry the leachresidue, but the leach residue may be taken, as it is drained l'roiiithe separator and iijiixed With suiicient dry ore or concentrate, andpartly sintei'edv material from a previous s'inter charge, to give thedesired' moisture for sintering, or about 10%. Asuitable apparatus forsintering the mixture of leachresidue and raw ore preparatory tosmeltiiig is described in vdetail in Patents No. 1,348,407, Aug. 3,1920,and No. 1,388,335,.Aug. 23, 1921. A mixture containing about 10%moisture and iionI 8% to 12% sulphur gives an excellent siiitei. lf thesulphur content is low, a littlc carbonaceous iuel, such as coal,charcoal, or colte, may be added.

Most copper deposits contain mixed sulphide and oxide ore. In suchcases, the concentrator tailings, instead ot' being. wwasted,l areleaclied to recover the copper in the ore in the Jforni of oxide. Theexcess acid from treating the sulphide concentrate is used to leach theoxide tailings, and the sulphur dioxide from` the roasting of thesulphide. roncentrate is used to reduce the ferrie saltsA roamed bydepositing the copper from the leach solution from the oxideconcentrator tailings.

It will be seen Afrom the accompanying flow sheet that tliecoppersolution may flow in :i closed circuit between the SO2 reducer and thecells or copper depositing tanks, u'liile a portion of the electrolyzedand regenerated solution isvflowed progressively throng-li the entiresystem.

It will be understood, for the purposeI of this invention, 'that itAdoes not makelany diii'erence whetl Iir'tlie niatte'is roasted Withthesulphide concentrate, or roasted sepaf rutely and then added. Forconvenience preference is given to' the iii-st method, altlioiiietallurgically they are equivalents.

The degree of impoverishment of copper solutions by electrolysis, asalso the amount ci copper extracted in the various step'sjof theprecious metal the process is optional with the operator. When he.thinks the copper is sufficiently removed in one` step he will proceedwith the next; This will naturally vary with the operator and with thenature of the material being treated.

l claim: y

1. A process of treating copper ores coinprising, concentrating the oreinto a sulphide concentrate, roasting the concentrate, leaching theconcentrate to extract a poi'-, tion ofthe copper, then smelting theleacliiei'l. concentrate residue to get the remainder of" the copperinto a matte, crushing the matte, adding the crushed matte to a newsulphide.concentrate chargeand repeating the cycle.'

2. A process of treating copper ore containing precious metalscomprising, concenetrating the ore into a sulphide concentrate..roasting the concentrate, leaching.. the roasted concentrateto extractaportion ot the'copper, then sineltingvthe leached concentrate to getthe remainder ot the copper and the precious iiietals into a matte, crusiing the matte, adding the crushed matte to a-new concentrate chargeand. repeating the cycle.

3. A process of treating copper' ore containing pilecious metalscomprising, treating the ore to orm a. concentrate, roasting theconcentrate, leaching the roasted concentrate tov extract a portion ofthe copper, then smelting the leaclied concentrate residue to get theremainder ot the copper and s into a matte, crushing the matte, addingthe crushed matte to a new concentrate charge, and repeating the cycleuntil thev mattev becomes suiiiciently ehrichedin the precious metals,and then recovering the precious metals trom the matte.

4. A process lot' treating copper ,ore coinprising, concentrating theore into a sulphide concentrate, roasting the concentrate, leaching theroasted concentrate, electrolyzing the leach solution to obtain theelec.- trolytic copper and regenerate the solution, returning theregenerated solution to the leaching tank and repeating the cycle untilthe copper is sii-iliciently extracted, then sinelting the leacliedresidue to obtain the residual values iii a matte, crushing the iiiatteand adding the niatte to a` new, charge ot sulphide concentrate.

5. A process of treating Copper ore comprising, concentrating the oreinto a sul phideconcentrate, roasting the concentrate, leaching theroasted concentrate, electrolyzing the leach solution to deposit thecopper and regenerate acid, applying sulphur dioxide troni the roastingfurnace to the electrolyzed solution and repeating the cycle ofreduction and electrolysis until the copper solution is suiiicientlydepleted in cop- .pe'r and regenerated in froid imd'then rei matte and,adding 'turning the regeiieretedfeeid Solu'lzion tothe centrate charge,eoneeiitrate end continuing the Cyele until meneer the matte to e newco'n- 9. Aprocese of treating copper orev con the- Copper in the roasted'concentrate-is pi'ising,'i'onst`ing lthe o're,"leniching"the roest#si-iiieiently extracted, then snielting the 'ed ore to extract aportionV of the copper,

leache'd residue to get the reiifiaiiiing values, Sii'ieltiiigtheleached residue to' get the re-` in :i rifatte, crushing the iii-ette,rindV :id-ding; iiieiniler 'of `the copper j in e, iniitte, and.

welding the nizi'ite to 'a new ore chuid Y' l0. A, processof'treeting'copper ore cointrezitiiig copper' .ore rconprising,roasting; the ore, legielnng Athe roestthe/eriished matte to*A iiyi'iewchargent con- 5. procees of 'teiniiig precious'i'neiils coniprieing,eo'iioe'n` ed nieto entrent n portion' 'of the' copper,

.tretinlr the ore into a sul )hide concentrate niixine ii conihiietihleund di ore' to the Wei1 Y rn 7 a 'in acid and then returning theregenerated si'iielt-ing the leiiohedlresidu'e to get the re;ueidsoiution tothe concentrnte'nnd nepeiit iniiiiider of the Copper andthe precious- Avefilhition to depoei roasting the, ,conceiitriite",'leaching' the/ leached ore residue to i'orin'ii siiiahlesin- Aron-steilconcentrate,eieotrolyizing tl-ieleeeh 'tering` Ainiggure, sineringvthemixture and t the copper .sind regenen Snielting the eiiiter to -ohtziinthe residual ete acid, applying sulphur ,dioxide 'frein-the valuesv inthe leziehed residue, in ii matte,

roestingrfurnnee to the eleetrolyzed solution uudediliiigthe.inatteof'iinew ore charge'.

il. A process of treating copper ore con- :ind repeating ehe .cycle 'ofreduction ind electrolysis untilfthe copper solution is suitainingprecious inetnle comprising, leiiclinig ticiently depleted in copper/andregenerated the oro to extractngportion of -the copper,

ing the cycle until the copper inthe roasted 'metals'- Ain emette,adding the niiitte'to a new concentrate is -sriiiieiently extracted,than ore charge-.eind repeetingfthe cycle -untilthe 1 sinel'ting thevleiinlied,.concentrate residue to iiiiitteis Suficientlz'yv enriched inthe precioue` get the fresidual values -iii :i iiiiitte, eriishmetals,then treating the-enriched i'iiiittelto ing the mette,endadding'thecrushed niiitte renover the precious `metals therefrom, and

'to e newcomz'entriite charge Lind-repeating adding. the' trentednihzitte residue to n new the cyele-until-the iniitte heconieesufiieiently ore oharge. enriched in the precious metals,- iind then l2.

proeeee of treating copper ore or reeoi'ering the preciousnietiiis-froni the concentrate containing preeiouel nietii'lscoinmatte.' l prieing, roastingthe ore, leaching the -roiist 'tainingpreeioue iiietiils Comprising;roast-L thenf-inixiiig the undiiedleiufiied residue iiigthe eriisheil nre,A iezu'fhing thefrozisted stillContaining both soluble und insoluble ore to extiriiet'n pi'ii'tion ofthe eopper,.tlien ejppenivith' otiii`1i'iiiiitei"iiil to he smelled,siiielting' the leiiclied resid-ne to got the ri Sinti-ring theini.\'tiii'e,' sineiting the sintr-r siduiil values iii inetto,'eriifiliinirthe in;itte,`ti-i `recover the remaining wallie?? oiB theadding',` the Crushed inzitte. "to .e new ore leiiihed residue in iiiniitte, crushing the charge und repentiiwig tirol-eroici until thenifi'tie, :indeiilding thevcruehed inzitte'to ai' -i i'iatteheooniesSuiliciently enriched iii pre` new' ore charge, roasting' the mixture,and

eious metals, then crushing the high grade repeating 'the cycle toiioeinnulsitetheprel viiiz'itt'e, roasting the inutie in. :i separateurvCioiis nletzile in n high grade nnitte.

'the-roasted ore,electrolyzing the Coi'iihined ing,l

ythe l'oziclied milite izo zi `new ore ehiifrggje.

copper. Solution io thev lem-h sointion' 'from coppeiiiiid sulphide oresof eoppei 'Containsoiution fto deposit the 'copper is the elec soliliide ore, ienehiiigl the'roiieted ore 'to er@ trolytie ini-tail,recovering the precious iii-:ict ii portion' of the copper,olectrolyxing 4inotuis" 'fi-oni the lmiuhrd inufite, und adding Ytheleucheolutioii to. deposit the copper zuid SQ A proeezls of treatingcopper ore eoineulphuimdioxide to the eleoi'roiv zei prisino, treatingthe ore ,to fohtnin :.iis'ulnele reducing :igent und renee-i, gziihegele i f v L). A. process or. treatingv oxideores of l'lO i'ieiousniet-als comprising, roue-ting the .phide concentrate sind :in i'ixidetiiiiing, of 'reduction und eiect'rolvsis until the ohi roiu'sting theconentrzrte, leaching iiie i'o-istlion is euiifiently delileted iiicopper and nu. Y ed. coiiceiitrete, applying SiilphuiI dioxideiegoiiorzited in :icid and their returning the ii'oin theiii-Listingtiiriince ,tothe leech eohi,n regenerated iieid solution tothe roasted orc tion, eloctifolyxing the leach solution to de rindcontinuingthe cycle until thecopperiii 'iosit the oo )er lindreo'enerzite iiei l, the roiisted ore i'ssiiiioientlv extracted, thenreturiiingii portion of the'regei'ieriitodincid Siiieltingr thelenclied' resiflie 'wget the re-l."4 'solution to the concentrate undapplying zi 'inem-ing ifiiluesvin a, rifatte, orueliingthi.`

port-ion to the oxide t'iiiling'zind continuing iiiati'e, adding,r -thecrju's'ned inzitte to ii new 'theoperution unt-il the copper inthe-concenoreAChei-ge for the roastingfurniice. und 'trate' isySuieent'ly extracted, then siiielting continuing the cycle of roastingand lea-chj the leached Concentrate residue te get the ing of the oreand matte whereby'excess acid 'residual values in n mette, crushing theproduced bv he eleetrolysis,ofI he lea-.ch 130- producedfto extractcopper from the oxide ore. I" 'auf 14. A process of vtreating lores ofcopper containing precious metals comprising, c oncentratinggthe' oreint'o'a sulphide concentrate, smelting the concentrate-into a mattecontaining the copper and precious metals,"

crushing the matte, roasting the crushed matte,`1eachin'g the roastedmaterial to eX-.

tract 'some of the copper, electrolyzingthe` resulting solutionltodeposit the copper and 'regenerate acid, returning lthe regeneratedacidl solution ,to4 the roasted material and continuing the cycle ofleaching and elecf trolysisof the leach solution' until' the copper inthe roasted'material is suiicientlyextracte'dfthen adding the leachresidue t'o anew ore charge and smelting the mixture and continuing thecycle of smelting, matte roasting, and leaching until the preciousmetals are suic'ientlyconcentrated in an enriched matte, and thenrecovering the copper .and precious metals vfrom the enriched matte.

containing precious metals comprising,

smelting'theore into a matte containing the copper and precious metals,crushing the matte, roasting the 'crushed matte', leaching the roastedmaterialto yextractsome of the copper, electrolyzing they resultingsolution tol-deposit the ,copper and regenerate acid, returning 'theregenerated acid solution' to the roasted material and "continuing thecycle of leaching and electrolysis of the l.solution and applying the'excess lacid so 15. 'A process of treating ores of copper' l25` leachsolution'untilthe copper in the' roasted ing the `leach residuecontainingv the precious charge .and smelting the, mixture and con--material is suiiciently extracted,`. then' addtinuing the 4cycleofsmeltiug', matte roasting', and leaching until the precious metals aresuiiciently concentrated in an enriched matte, then recovering some ofthe precious 'metal and copper values from-the enriched matte, and thenadding'zthe resultingmatte' leach residue to a ne'w smelter charge.

' WILLIAM' E.

